In English Grammar in Use, it is said that we have to use past simple instead of present perfect for things that are not recent or new:
Use the past simple (not the present perfect) for things that are not recent or new:
Mozart was a composer. He wrote more than 600 pieces of music. (not has been ... has written)
However, later in the same book, there is the following example:
Fireworks are supposed to have been invented in China.
Tell me if I'm wrong but it is present perfect ; for simplicity, we can rephrase the above sentence like this:
Fireworks have been invented in China.
It seems to be a contradiction. The invention of the fireworks is not a recent event. According to the first example, we should use past simple.
In this answer, it is said:
There is no limit on how far back an event occurred, the only requirement is that we are talking about the state or effects of the event in the present.
Should I conclude we can use present perfect for recent events and English Grammar in Use is wrong about that?